ES2683369T3 - Heat integrated distillation apparatus - Google Patents

Abstract

A heat integrated distillation apparatus comprising: - a high pressure column (1) comprising a bottom of the column (1a), a top of the column (1c) and a packed or packed bed section (1b) , said tray or packaging bed section (1b) used as a grinding section; - a low pressure column (2), located above said high pressure column (1), said low pressure column comprising a bottom of the column (2a), a feeding phase (2f), a bed section in tray or packaging (2b) used as a removal section and a portion corresponding to the rectification section (2g) located above the feeding phase (2f); - a first pipe (26) connecting the bottom of the column (1a) of said high pressure column (1) with the portion corresponding to the rectification section (2g) of said low pressure column through means (6 ) to supply a liquid that remains at the bottom of the column (1a) of said high pressure column (1) to the portion corresponding to the rectification section (2g) of said low pressure column (2); - a heat exchanger (8) located in a phase at the bottom of said low pressure column (2); characterized in that the distillation apparatus further comprises: - a second pipe (23, 4a) connecting the portion corresponding to the rectification section (2g) with said heat exchanger (8) at the bottom of the low pressure column ( 2); - a compressor (4) installed in said second pipe (23, 4a) and configured to compress steam from the portion corresponding to the rectification section (2g) and then supply the compressed steam to said heat exchanger (8) at the bottom of the low pressure column (2); and - a third pipe (30) that introduces fluid that flows from said heat exchanger (8) in the lower part of said low pressure column (2) to the bottom of the column (1a) of the high pressure column (1 ).

Description

DESCRIPTION

Heat integrated distillation apparatus 5 BACKGROUND OF THE INVENTION

1. Field of the invention

The present invention relates to a distillation apparatus that performs a distillation operation widely applied to many industrial processes, and more particularly, to a heat integrated distillation apparatus.

2. Description of the related technique

Distillation separation is a unit operation widely applied to industrial processes in general, 15 but consumes a large amount of energy. In the industrial field, therefore, studies have been conducted on distillation systems that save energy. These studies have led to the development of a heat-integrated distillation column (hereinafter referred to as HIDiC) as a distillation apparatus that saves a lot of energy.

As shown in Figure 1, a basic HIDiC system has a structure in which a rectification section (high pressure unit) and a removal section (low pressure unit) are provided so that they are separated between st The operating pressure of the rectification section is set higher than that of the removal section so that the operating temperature of the rectification section can be higher than that of the removal section. This allows a reduction in the amount of heat that is supplied to a calderm because heat transfer occurs from the rectification section to the removal section when there is a heat exchange surface between them. The heat of the rectification section moves to the removal section and, therefore, the amount of heat that is supplied in a calderm can be reduced. As a result, a high energy saving distillation apparatus can be achieved.

30 In order to implement the concept of HIDiC, several distillation devices have been proposed that have double tubena structures, that is, double tubena structures consisting of internal tubenas that form rectification sections and external tubenas that form removal sections (see JP2004-16928A). These configurations are described as capable of reducing the amounts of heat that are supplied to the boilers and the amounts of heat that are eliminated in the condensers, since heat transfer occurs from the 35 rectification sections (internal tubenas) to the sections of removal (external tubenas).

However, the heat integrated distillation apparatus having the rectification section and the removal section formed in the double pipe structures as discussed in Patent Bibliography 1 issues the following problems 1) to 6).

40

1) The product cannot be obtained with lateral cutting current. The lateral cut means that a product is extracted as an intermediate distillate product, during a distillation process until a final distillate is acquired from the top of the column.

In the distillation apparatus described in JP2004-16928A, the tubena units of the double tubena structures are arranged to come into contact with each other. In addition, the outer tubenas and the internal tubenas are equipped with structured packing. As a result, a tubena arrangement cannot be formed to extract any intermediate distillate product from the internal tubena of each tubena unit. Consequently, the structure disables lateral cutting.

50 2) The power phase in which the power supply is provided cannot be optimized. This is because, in the rectification section and the removal section formed in the double pipe structures, their packing heights are equal, disabling the free configuration of the number of phases of the rectification section and the section of removal.

55 3) The feed phase cannot be changed to comply with the feed current composition. This is due to the structure in which the free configuration of the feeding phase position is disabled as described in 2).

4) The multiple feed current (reception of a plurality of feed streams) cannot be treated. This is due to the structure in which no supply current can be supplied in the middle of the

double tubenas as described in 1).

5) The maintenance of the device is difficult. Tubena units using structured packing are densely arranged so that they are adjacent to each other as described in 1). This disables access.

5 complete to the desired tubena unit, and maintenance thereof cannot be performed.

6) The heat exchange rate between the rectification section and the removal section that uses double tubenas and in which there is no degree of design freedom to design the heat transfer area, depends solely on the temperature profile of Distillation column Therefore, in the design of the apparatus, the degree of

10 freedom in the design of the heat exchange rate is small.

Q, the rate of heat exchange between the rectification section and the removal section, is represented by Q = U x A x AT, where U is a global heat transfer coefficient, A is a heat transfer area, and AT is a temperature difference between the rectification section and the removal section. In the HIDiC using the double tubena structure, an internal tubena wall surface becomes a heat transfer area. This heat transfer area has a fixed value determined by a structure of the double tubenas. The overall heat transfer coefficient also has a fixed value determined by the heat transfer structure and the physical properties of the fluid involved in the heat exchange. Therefore, as can be understood from the heat exchange rate formula, a heat exchange rate in the design specification can be changed based only on the temperature difference between the rectification section and the removal section , which changes due to the operational pressure of the rectification section and the removal section.

As the heat integrated distillation apparatus that can solve the problem described above, the present applicant has proposed the apparatus of JP4803470B.

Figure 2 shows a first example of the distillation apparatus described in JP4803470B. The distillation apparatus includes a rectification column 1, a removal column 2 located higher than the rectification column 1, a first pipe 23 for communicating the upper part of column 2c of the removal column with the bottom of the column 1a of the rectification column, and a compressor 4 configured to compress the steam from the top of column 2c of the removal column to supply the compressed steam to the bottom of column 1a of the rectification column. The distillation apparatus further includes a tube-type heat exchanger 8 located in a predetermined phase of the rectification column 1, a liquid extraction unit 2d located in a predetermined phase of the removal column 2 and 35 configured to extract a part of the liquid of the predetermined phase outside the column, a second pipe 24 to introduce the liquid from the liquid extraction unit 2d to the heat exchanger 8, and a third pipe 25 to introduce fluids introduced through the second pipe 24 to the heat exchanger 8 and then discharge it from the heat exchanger 8 to a phase directly below the liquid extraction unit 2d.

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With the configuration described above in Figure 2, fluids flow from the removal column 2 to the heat exchanger 8 of the rectification column 1 through the second pipe 24. The heat is removed from the steam of the rectification column 1 in the heat exchanger 8. Then, heat can be transferred from the rectification column 1 to the removal column 2 through the third pipe 25. The fluids flow from the removal column 2 to the rectification column 1 by gravity. Accordingly, the fluids in the heat exchanger 8 are pushed to flow from the rectification column 1 to the removal column 2. In other words, this heat integrated distillation apparatus employs a thermal siphon system and, therefore, , a pressure supply means, such as a pump, is not necessary to supply the liquid from the rectification column 1 to the removal column 2 located above in a vertical direction.

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Figure 3 shows a second example of the distillation apparatus described in JP4803470B. The distillation apparatus includes a rectification column 1, a removal column 2 located higher than the rectification column 1, a first pipe 23 to connect the upper part of column 2c of the removal column with the bottom of the column 1a of the rectification column, and a compressor 4 that compresses steam from the top of column 2c of the removal column to supply the compressed steam to the bottom of column 1a of the rectification column. The distillation apparatus further includes a liquid sump unit 2e located in a predetermined phase of the removal column 2 and configured to contain liquid that has flowed down, a heat exchanger 8 located in the liquid sump unit 2e, a separation plate 16 which is adjusted in a predetermined position of the rectification column 1 and configured to separate upper and lower phases completely, a second pipe 29 to introduce steam below

from the separation plate 16 to the heat exchanger 8, and a third pipe 30 to introduce fluids introduced through the second pipe 29 to the heat exchanger 8 and then discharge them from the heat exchanger 8 to an upper side of the separation plate 16.

5 With the configuration described above in Figure 3, the steam is extracted from the rectification column 1 through the second pipe 29. The steam is introduced into the heat exchanger 8 in the removal column 2. Then, the heat it can be transferred from the rectification column 1 to the removal column 2. The high pressure steam in the rectification column 1 ascends through the second pipe 29 to the heat exchanger 8 in the removal column 2. Accordingly, a Partial or fully condensed steam fluid in the heat exchanger 10 is pushed from the removal column 2 to the third pipe 30 out of the column. Therefore, this configuration also does not require any means of supplying pressure, such as a pump, for the supply of liquid from the removal column 2 to the rectification column 1 located on a lower side in a vertical direction.

The configurations of the apparatus of Figures 2 and 3 described above are capable of reducing the amount of heat that is removed in the condenser 7 that is attached to an upper part of the rectification column 1, and of reducing the amount of heat of the Caldenn 3 attached to the lower part of the removal column 2 more, compared to an ordinary distillation apparatus having a column in which an upper side is a rectification section and a lower side is a removal section with a place of power as a limit thereof, and 20 which is not of a heat integrated type. As a result, it is possible to provide a distillation apparatus of energy efficiency.

The rectification column 1 and the removal column 2 can be configured using tray sections or packed bed sections similar to those of a general distillation apparatus. Therefore, the apparatus can address the side cut or the multiple feed current without the need for any improvement, and it is possible to easily perform the maintenance of the apparatus. For the same reason, the number of phases of the rectification column or the removal column can be freely configured, and a feeding phase can be optimized.

30 A heat transfer area can be freely adjusted and, therefore, the heat exchange rate can be determined without any dependence on the temperature difference between the columns.

As described above, according to the example of the apparatus described in JP4803470B (Figures 2 and 3), the energy efficiency is high, the lateral cut and the adjustment of a feeding phase position can be easily treated, and maintenance The device is easy. In addition, the apparatus of the present invention has a structure in which the degree of design freedom is high and, therefore, can be easily accepted by the user side.

Incidentally, with respect to the distillation apparatus shown in Figures 2 and 3, the present inventors 40 intend to further improve the energy efficiency, and the respective examples of distillation apparatus still have the following space to be improved.

In other words, in the distillation apparatus shown in Figure 2, the following procedure is adopted. Part

0 all of a liquid in an arbitrary phase of the removal column 2 is removed through the pipe 24 24 outside the column, and is supplied to the tube-type heat exchanger 8 located in an arbitrary phase of

rectification column 1, where heat exchange is performed. Subsequently, part or all of the amount of liquid that is removed from the removal column 2 is vaporized by steam in the rectification column.

1 at a higher temperature, and returns directly below the liquid removal position described above of the removal column 2 through the pipeline 25 outside the column by an effect of

50 thermal siphon, without energy supplied from the outside by a pump or similar. This circulation of the fluids is performed.

In such a procedure, a liquid head is needed on the supply side of the tubular beam type heat exchanger 8 (tubena 24 outside the column) to perform the circulation of the fluids by the thermal siphon effect. In other words, as the portions extending in the vertical direction of the tubenas 24 and 25 lengthen correspondingly with respect to the distance (height) between the liquid extraction position X of the removal column 2 and the position of installation of the heat exchanger And of the rectification column 1, the pressure loss through the pipe 25 increases. Therefore, to circulate the fluids overcoming this, the liquid head based on the inlet position of the heat exchanger 8 (final portion 60 of the tubena 24 connected to the heat exchanger 8) is also made large. However, in the

The heat exchanger tube 8 the pressure becomes high and the boiling point increases due to the increase in the liquid head. Therefore, the temperature difference between the inside of the tubena and the outside (casing) of the tubena in the heat exchanger 8 is reduced correspondingly to the boiling point increase. To compensate for this, the need arises to increase the pressure of the rectification column 1, that is, 5 to increase the temperature in the rectification column 1 by increasing the compression ratio of the compressor 4. Therefore, there is a space that can be improve from the point of view of energy saving performance.

In other words, in the distillation apparatus shown in Figure 3, the following procedure is adopted. The separation plate 16 which completely divides the interior of the column into an upper side and a lower side 10 is installed in an arbitrary phase of the rectification column 1, all the steam rising from the lower separation plate 16 is extracted of the column through the pipe 29, and is supplied to the tube-type heat exchanger 8 installed in an arbitrary phase of the removal column 2, where the heat exchange is performed. Next, a partially or fully condensed fluid in the heat exchanger 8 flows through the tubena 30 out of the column to the upper side of the separation plate 16 in the rectification column 1 by 15 gravity, and the condensed liquid flows through another pipe 31 to move to the lower separation plate 16. Such fluid circulation is performed.

Such a procedure is intended to extract all the steam in the rectification column 1 outside the column and, therefore, adopts a complicated structure in which the separation plate 16 is installed in the rectification column 20, and the condensed liquid fed into the separation plate 16 from the removal column 2 is further transferred to a lower lateral space of the separation plate 16 through the pipe 31 and the control valve 17 outside the column. Therefore, there is a space that can be improved from the point of view of the structure and manufacturing cost.

In addition, the driving force for the fluids that pass through the heat exchanger tube 8 is obtained by giving pressure loss on the upper and lower sides of the separation plate 16 and, therefore, the bottom pressure. column 1a must be greater than the pressure of the upper part of column 1c of the rectification section 1 correspondingly to the loss of pressure on the upper and lower sides of the separation plate 16. Therefore, the need arises of setting a higher pressure on an outlet side of the compressor 4 (specifically, increasing a compression ratio) correspondingly to increase the pressure on the bottom side of column 1a. Therefore, there is also a space that can be improved from the point of view of energy saving performance.

To further improve the two examples of configuration of the apparatus of Figures 2 and 3 as above, the present inventors pay attention to the circumstances indicated below.

When the phases for performing the lateral heat exchange between the removal section and the rectification section are optimally selected, to put the concept of the HIDiC into practical use, the lowest phase of the rectification section is not used for the exchange of heat with the removal section in some cases. Figure 4 shows a conceptual configuration of the HIDiC in this case, and Figures 5 and 6 show examples of how to perform the HIDiC in this case. In particular, Figure 5 shows the application of the heat transfer system of the apparatus of Figure 2 to the conceptual configuration of Figure 4, and Figure 6 shows the application of the heat transfer system of the apparatus of Figure 3 a the conceptual configuration of Figure 4.

As is understandable with reference to the configurations of Figures 4 to 6, a single phase or a plurality of phases at the bottom of the rectification section 1d is not or is not involved at all in the heat exchange in many cases. . This not only applies to the tray, but also to the packed bed layer. In the above configurations, the lower part of the rectification section 1d, which has the highest temperature, is not used effectively for heat exchange.

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In the configurations in which the lower part of the rectification section 1d is not used for heat exchange with the removal section as in Figures 4 to 6, there is no need to connect the outlet pipe of the compressor 4 to the bottom of column 1a (the lowest portion of the rectification section) of the rectification column. Rather, connect the outlet pipe 4a of the compressor 4 to the heat exchange section 55 (heat exchange section directly above the bottom of the rectification section 1d) which is located in the lowest position of the rectification section does not waste heat. However, if the outlet pipe 4a of the compressor 4 is directly connected to the heat exchange section located in the lowest position of the rectification section without being directly connected to the lowest part of the rectification section, there will be no gas in the lower part 1d, which is located below it, of the rectification section and, therefore, the distillation operation having a liquid-vapor equilibrium according to the removal principle is not

establishes. Therefore, the device using this connection procedure cannot be performed.

Therefore, the present inventors have decided to move and arrange the region 2g (the region shown by the dotted line in Figure 4), which corresponds to the bottom 1d of the rectification section, to a location that is 5 by above the top of the removal column (in other words, above the feeding phase 2f), as shown in Figure 4, for example. The arrangement in this way does not change the flow of fluids at all, and if the phase of the lower part 1d of the rectification section moves and is arranged above the feeding phase 2f, region 2g, which corresponds to the lower part of the rectification section can be operated under the pressure of the removal column 2 which is less than the pressure of the rectification column 1. 10 As a result, the relative volatility in the region 2g becomes large, and the energy (amount of heat) in itself that is originally necessary for a separation process can be reduced.

In addition, in the case of the configuration in which the outlet pipe 4a of the compressor 4 is connected to the position directly above the lower part 1d of the rectification section, as shown by the 15 dots in the Figures. 4 to 6, the steam from the outlet pipe 4a of the compressor 4 is supplied to the rectification column 1, and from the rectification column 1, the heat is transferred to the heat exchange section 2h at the bottom of the removal column 2, and returns to the position of the rectification column 1 to which the outlet pipe 4a is connected, again. The present inventors have considered that, if that is the case, the adoption of such an apparatus configuration is more preferable, than the outlet pipe 4a of the compressor 4 is directly connected to the heat exchange section 2h at the bottom of the removal column 2 without being connected all the way to the rectification column 1, and that the fluids that are subjected to heat exchange in the heat exchange section 2h are introduced into the rectification column 1.

In the case of the configuration of the apparatus based on the above concept, the configuration of the apparatus of Figure 5 25 becomes a configuration of the apparatus of Figure 7, and the configuration of the apparatus of Figure 6 becomes a configuration of the apparatus of Figure 8, although the details thereof will be described later. According to the configurations of the apparatus of Figures 7 and 8, between a plurality of heat transfer systems that perform heat exchange between various phases of the respective low pressure column and a high pressure column, in a heat transfer system provided between the bottom of a low pressure column and the bottom of a high pressure column, the high pressure steam of the compressor 4 is fed directly to the heat exchanger 8 at the bottom of the low pressure column, and the high pressure steam that provides heat to the bottom of the low pressure column through the heat exchanger 8 is introduced into the rectification column 1, as shown in Figures 7 and 8. In this transfer system of heat, both the configuration of the apparatus of Figure 2 and the configuration of the apparatus of Figure 3 are improved. The reason for this is as follows.

That is, in the examples of apparatus of Figures 2 and 5, the circulation of the fluids by the effect of the thermal siphon is used to perform the heat exchange between the rectification section and the removal section, and to make the fluid circulate, a liquid head is needed on the supply side (tubena 24 outside the column) of the tubular beam type heat exchanger 8. However, the configuration of the apparatus of Figure 7 does not need a liquid head in some heat transfer systems and, therefore, an improvement in energy saving performance is expected.

Meanwhile, in the example of the apparatus of Figure 3, the high pressure steam that is supplied to the rectification column 1 is moved towards the removal column 2 through the pipe 29 outside the column, and the fluids which are partially or totally condensed in the heat exchanger 8 of the liquid sump unit 2e in the removal column 2 return to the rectification column 1 through another pipe 30. For this purpose, it is necessary to divide the interior of the rectification column 1 completely with the separation plate 16, connect the pipe 29 to a lower space of the separation plate 16, and connect the pipe 30 to an upper space 50 of the separation plate 16 to establish the space pressure bottom of the separation plate 16 to be higher. But, the configuration of the apparatus of Figure 8 does not require a pressure difference in some heat transfer systems and, therefore, an improvement in energy saving performance is expected.

55 SUMMARY OF THE INVENTION

An objective of the present invention is to improve the points mentioned above in both examples of apparatus configuration of Figures 2 and 3 as described above, and achieve greater energy savings.

A heat integrated distillation apparatus according to one aspect of the present invention includes:

a high pressure column corresponding to a region above a heat exchange section located in the lower part within a region that includes a tray section or a packed bed section 5 that is used as a rectification section; Y

a low pressure column that is located above, as seen from the high pressure column, and that integrates a region that includes a tray section or a packed bed section that is used as a removal section, with a portion corresponding to the rectification section that corresponds to a region that is located below the heat exchange section located at the bottom in the rectification section.

10

The portion corresponding to the rectification section is located in an upper portion of the removal section in the low pressure column so that the portion corresponding to the rectification section continues towards the removal section.

15 In addition, the aspect described above includes:

a first pipe connecting a column bottom of the high pressure column with the portion corresponding to the rectification section through means that pressurize a liquid that remains at the bottom of the column of the high pressure column to the portion corresponding to the rectification section;

20 a heat exchanger located in a phase in a lower part (may be a lower phase or not) of the low pressure column;

a second pipe connecting the portion corresponding to the rectification section with the heat exchanger in a lower part of the low pressure column;

a compressor installed in the second pipe and configured to compress steam from the portion corresponding to the rectification section and then supply the compressed steam to the heat exchanger at the bottom of the low pressure column; Y

a third pipe introducing fluids that flow from the heat exchanger in the lower part of the low pressure column to the bottom of the column of the high pressure column.

30 In the above aspect, high temperature steam through the compressor is introduced into the heat exchanger located at the bottom (not limited to the lower phase) of the low pressure column, and the fluids flowing out from the heat exchanger they are introduced in the lower part of the high pressure column, whereby heat is provided to the lower part (not limited to the lower phase) of the low pressure column, and the fluids that are introduced into The bottom of the high pressure column can be cooled. The heat transfer system 35 (side heat exchange section) using the second and third tubenas and the heat exchanger in the low pressure column is configured as if a side condenser is installed in the lower part phase of the high pressure column, and a lateral caldenn is installed in the phase of the lower part (not limited to the lower part) of the low pressure column. Therefore, in comparison with a distillation apparatus that does not include the heat transfer system described above, the amount of heat that is removed can be further reduced in the condenser, and the amount of heat that is supplied can be further reduced by The caldenn.

In particular, the heat transfer system described above that allows heat exchange between the lower part of the low pressure column and the lower part of the high pressure column is configured to introduce the high pressure steam from the compressor directly into the heat exchanger provided in the low pressure column and thus to feed the condensed fluids in the heat exchanger to the high pressure column. That is, the configuration does not require a liquid head as in the example of the apparatus of Figure 2, or the loss of pressure is not required as in the example of the apparatus of Figure 3. Therefore, the saving efficiency of Energy can be improved because the liquid head and pressure loss are not necessary. In addition, the region corresponding to the lower part of the rectification section (portion corresponding to the 50 rectification section) may function due to the pressure of the low pressure column that is less than the pressure of the high pressure column and, therefore, in comparison with the configurations of Figures 4 to 6, the relative volatility in the portion corresponding to the rectification section increases. Therefore, the energy itself (amount of heat) that originally becomes necessary for a removal process can be reduced.

From the above, the distillation apparatus can be provided with extremely high energy efficiency.

The rectification section and the removal section, or the high pressure column and the low pressure column, are configured using tray sections or packed bed sections similar to those of a general distillation apparatus. Therefore, the apparatus can address the side cut or multiple feed current without

the need for any improvement, and it is possible to easily perform the maintenance of the apparatus. For the same reason, the number of phases of the rectification section or the removal section can be freely configured, and the feeding phase can be optimized.

5 In addition, a heat transfer area can be freely adjusted and, therefore, the heat exchange rate can be determined without any dependence on the temperature difference between the columns.

According to the present invention, the energy efficiency is high, the lateral cut and the adjustment of a feeding phase position can be easily treated, and the maintenance of the apparatus is easy. In addition, the apparatus of the present invention has a structure in which the degree of design freedom is high and, therefore, can be easily accepted by the user side.

Furthermore, according to the present invention, the points mentioned above in both examples of apparatus configuration of Figures 2 and 3 are improved, and greater energy savings can be achieved.

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BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 shows a basic structure of the HIDiC;

Figure 2 is a schematic configuration diagram showing an example of a distillation apparatus which is a relevant related technique and is described in JP4803470B;

Figure 3 is a schematic configuration diagram showing another example of the distillation apparatus that is a relevant related technique and described in JP4803470B;

Figure 4 is a conceptual diagram of the apparatus shown to explain the circumstances of the objective of the invention of the present application;

Figure 5 shows a way of performing an apparatus configuration of Figure 2 based on the conceptual configuration of Figure 4;

Figure 6 shows a way of performing an apparatus configuration of Figure 3 based on the conceptual configuration of Figure 4;

Figure 7 shows a general configuration of a heat integrated distillation apparatus according to an embodiment 30 of the present invention;

Figure 8 shows a general configuration of a heat integrated distillation apparatus according to another embodiment of the present invention;

Figure 9 shows a peripheral configuration of a tubular beam type heat exchanger located in a low pressure column of each of Figures 7 and 8;

Figure 10 shows a configuration of a liquid extraction unit located in a high pressure column of each of Figures 7 and 8; Y

Figure 11 shows a peripheral configuration of a tube-type heat exchanger located in the high pressure column of each of Figures 7 and 8.

40 [EXPLANATION OF THE LETTERS]

1 rectification column (called high pressure column in the embodiments of Figures 7 and 8).

1st column bottom

1b tray section (or packed bed section)

45 1c top of the column

1d the bottom of a rectification section

2 removal column (called low pressure column in the embodiments of Figures 7 and 8).

2nd column bottom

2b tray section (or packed bed section)

50 2c upper part of the removal section

2d liquid extraction unit

2e liquid sump unit

2f feeding phase

2g region that corresponds to the bottom of a rectifier section 55 3 heater (calderm)

4 compressor

4th Tubena

5 chimney tray for sump

6 bomb

60 7 condenser

8 tubular beam type heat exchanger

9 chimney tray for sump

10, 12, 14 Liquid

11, 13, 18 steam

5 15 chimney tray for sump 16 separating plate 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 tubena

X a liquid extraction position of a removal column

And a heat exchanger installation position of a rectification column

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DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENT

A heat integrated distillation apparatus according to the present invention has a basic feature in which a column casing (low pressure column) is the result of adding a region used as a removal section that extends in a vertical direction, and a region (or a portion corresponding to the rectification section) that corresponds to a region that is below a lateral heat exchange section in the lower phase between the heat exchange lateral sections installed in the rectification section, and a column housing (high pressure column) that includes a region, except for the region mentioned above, which corresponds to the rectification section of the rectification section extending in the vertical direction, are provided separately, and the low pressure column is located above as seen from the high pressure column. A general distillation apparatus, which is not an internally integrated heat distillation apparatus, includes a column that is constructed in the vertical direction and that has a column bottom, a tray section (or packed bed section), and a upper part of the column, in which, at the limit of a feeding location, an upper side of the tray section (or packed bed section) is a rectification section and a lower side is a removal section, and The general distillation apparatus is totally different from the heat integrated distillation apparatus according to the present invention. In particular, an arrangement described below uses both configurations of the distillation apparatus of Figures 2 and 3 that the present applicant has already proposed. Therefore, an embodiment of the present invention will be described using the same reference signs for the same components as those shown in Figures 2 and 3.

Figure 7 shows a general configuration of a heat integrated distillation apparatus according to an embodiment of the present invention. The heat-integrated distillation apparatus according to the embodiment comprises a high pressure column 1 corresponding to a remaining region of a rectification section that excludes a region corresponding to phases located below a lateral heat exchange region that is perform in the lowest part within the rectification section; and a low pressure column 2, which is the result of the addition of a global removal section located above as seen from the high pressure column 1, and the bottom of the rectification section mentioned above. The high pressure column 1 includes the bottom of column 1a, the tray section (or the packed bed section) 1b, and the top of column 1c. The low pressure column 2 also includes the bottom of the column 2a, the tray section (or the packed bed section) 2b, the upper part of the removal section 2c and the lower part of the rectification section 2g which It will be described later.

In addition, as described using Figures 4 and 5 in the SUMMARY OF THE INVENTION section, the high pressure column 1 of the embodiment corresponds to the region (upper part of the rectification section) that remains after the part The lower part of the rectification section 1d is cut from the rectification column 1 of Figure 5, and the region (hereinafter referred to as the portion corresponding to the rectification section 2g), which corresponds to the lower part of the rectification section 1d that is cut from the rectification column, is located above the upper part of the removal section 2c of the low 50 pressure column 2. In the configuration in which the upper part of the upper part of The low pressure column can be used as the portion corresponding to the rectification section 2g so, the portion corresponding to the rectification section 2g can be operated under the pressure of the low pressure column. esion 2 whose pressure is lower than the pressure of the rectification column 1 of Figure 5. Therefore, the relative volatility in the portion corresponding to the rectification section 2g becomes large, and the energy itself (amount of heat) that is originally needed for a separation process can be reduced.

Tray sections 1b and 2b are sections in which several horizontal trays are located. The space between adjacent trays is called phase. In each phase, when the contact is made with liquid gas, a mass transfer occurs. As a result, the gaseous phases rich in components that have a higher volatility amount to a higher phase, while a liquid phase rich in components that have a higher

Lower volatility drops to a lower phase. Then, the contact with the gas-liquid is executed again with a new liquid phase or gas phase so that a mass transfer occurs. Therefore, there are abundant components that have higher volatility in a higher phase of the column, there are abundant components that have lower volatility in a lower phase, and a distillation operation is performed.

5

The packaged section that can replace the tray section is a section in which a certain packing is installed in the empty column, and the contact with the liquid-gas is executed on its surface. By the same mechanism as that of the tray section, there are abundant components that have a higher volatility in an upper part, there are abundant components that have a lower volatility in a lower part and a distillation operation is performed. In Figure 7, tray sections 1b and 2b (or packed bed sections) are shown in white. In reality, however, the structures mentioned above are used.

Each high pressure column 1 and low pressure column 2 is described in detail. First, the low pressure column 2 is described.

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The heater 3 referred to as a caldenn is disposed outside the bottom of the column 2a of the low pressure column 2, and the pipe 21 is provided from a lower part of the space at the bottom of the column 2a through the heater 3 to a upper part of the space at the bottom of column 2a. Therefore, the liquid that descends through the tray section 2b (or packed bed section) of the low pressure column 20 remains at the bottom of the column 2a. A part of the liquid is heated by the heater 3 to become steam and ascends to the top of the column. From the bottom of the bottom of column 2a, funds that are rich in components with lower volatility are acquired through pipeline 22.

The upper part of the removal section 2c in the low pressure column 2 is a position for supplying feed stream and, in this region, the feeding phase 2f is provided. As described above, the portion corresponding to the rectification section 2g is located above the removal section in the low pressure column 2 (specifically, above the feeding phase 2f). The portion corresponding to the rectification section 2g and the upper part of the removal section 2c in the low pressure column 2 are connected so that the interior of the portion corresponding to the rectification section 30 2g and the interior of the part top of the removal section 2c come into contact with each other. According to the embodiment, the feed stream is supplied at the top of the removal section column 2c in the low pressure column 2, but if the feed location must correspond to a change in the composition of the feed stream, The feeding location may be in an arbitrary phase of the tray section 2b (or packed bed section). Even when there is a plurality of feeds, the location of the feed can be the top of the removal section 2c in the low pressure column 2, and other arbitrary phases (including a phase of the high pressure column 1).

The tray section 2b (or packed bed section) of the low pressure column 2 includes a liquid extraction unit 2d at a predetermined stage. The liquid extraction unit 2d is in a phase located 40 on an upper side of the liquid sump unit 2e which will be described later. As shown in Figure 9, the liquid extraction unit 2d maintains the liquid 10 that descends from above in the chimney tray for the sump 5, and extracts a part of the liquid 10 outwards from the low pressure column 2 The pipe 24 for directing a part of the liquid 10 to the high pressure column 1 is connected to the liquid extraction unit 2d. The pipe 25 of the high pressure column 1 is inserted through a housing wall 45 of the low pressure column 2 in a phase directly below the liquid extraction unit 2d. From the tubena 25 inserted in the phase directly below the liquid extraction unit 2d, fluids having a mixture of vapor 11 and liquid 12 are introduced as described below, and the vapor 11 rises while the liquid 12 descends.

50 In addition, the tray section 2b (or packed bed section) that is closer to the bottom of the column 2a of the low pressure column 2 includes the liquid sump unit 2e. The liquid sump unit 2e stores a predetermined amount of liquid 10 that has flowed into the chimney tray for the sump 15, and the spilled liquid from the chimney tray for the sump 15 drips. In order for the tubular tube heat exchanger 8 to be submerged in the liquid stored by the liquid sump unit 55 2e, the tubular beam type heat exchanger 8 is located in the liquid sump unit 2e (see Figure 11). The parallel pipe portions 8a and 8b in the U-shaped pipe of the tube-type heat exchanger 8 are arranged along the chimney tray for the sump 15.

The pipe 4a (see Figure 7) connected to an outlet of the compressor 4 is connected to the upper pipe portion 60 8b of the parallel pipe portions. Tubena 30 (see Figure 7) to feed fluids from the

low pressure column 2 to the bottom 1a of the high pressure column 1 is connected to the bottom pipe portion 8a. The portion corresponding to the rectification section 2g located in the low pressure column 2 is connected to an inlet of the compressor 4 through the pipe 23.

5 An operation of the heat exchanger 8 in the liquid sump unit 2e is described.

In the distillation apparatus described above, a feed liquid descends from the top of the removal section 2c (feed phase 2f) in the low pressure column 2 through a tray or a packed layer. Liquid 10 (see Figure 11) remains in the liquid sump unit 2e in the chimney tray for sump 15 which is located in an arbitrary phase. The U-shaped tubena of the tubular beam heat exchanger 8 is located in the liquid sump unit 2e and, therefore, the U-shaped tubena is submerged in the liquid 10. In this phase, the steam of High temperature through the compressor 4 is introduced through the pipe 4a into the upper pipe portion 8b of the heat exchanger 8 in the liquid sump unit 2e. At this time, a part of the liquid 10 in contact with the housing wall of the 15 portions of tubena 8b and 8a, where the high temperature steam moves, is heated to become the steam 18 and rises (see Figure 11 ). The liquid that remains without becoming steam descends through an exit gate. The high temperature steam introduced through the pipe 4a in the heat exchanger 8 in the low pressure column 2 is partially or totally condensed and transformed into a liquid phase from a gas phase while moving from the upper pipe portion 8b to the bottom tube portion 8a. The liquid that 20 is generated by the condensation and the vapor that does not condense passes through the pipe 30 which is located outside the column and then is fed to the bottom of the column 1a of the high pressure column 1 (see Figure 7).

The high pressure column 1 is further described.

25

One end of the pipe 26 is connected at the bottom of the bottom of the column 1a of the high pressure column 1, while the other end of the pipe 26 is connected to the portion corresponding to the rectification section 2g located above from the top of the removal section 2c (feed phase 2f) in the low pressure column 2. To recycle the liquid, which remains at the bottom of column 1a of the high pressure column 1, at the portion corresponding to the rectification section 2g, the pump 6 is needed in the intermediate section of the pipe 26.

The condenser 7 is equipped outside the upper part of the column 1c of the high pressure column 1, and the tubena 28 is connected from a part of the upper space of the upper part of the column 1c to the condenser 7. Therefore , the vapor that has moved to the top of the column 1c of the high pressure column 1 is cooled by the condenser 7 to become liquid, and a distilled liquid is acquired that is rich in components that have high volatility. A part of the liquid is refluxed to the top of column 1c whenever necessary.

40 In addition, the tubular beam type heat exchanger 8 is inserted in a phase that is located above the position where the tubena 30 is connected, from the tray section 1b of the high pressure column 1. The tubena portions Parallel to the U-shaped pipe of the tube-type heat exchanger 8 are placed along the chimney tray for sump 9 to temporarily retain the condensed liquid and to redistribute the vapor rising from below. The lower pipe portion 8a of the parallel pipe portions 45 is connected to the pipe 24 connected to the liquid extraction unit 2d of the low pressure column 2. The upper pipe portion 8b is connected to the pipe 25 Insert in the phase directly below the liquid extraction unit 2d.

An operation of the tube-type heat exchanger 8 is described.

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In the apparatus, the pressure and the temperature of the steam leaving the portion corresponding to the rectification section 2g are increased by the compressor 4. Subsequently, a part or all of the steam is condensed by the heat exchanger 8 in the column low pressure 2, and is supplied to the bottom of column 1a of the high pressure column 1. The steam 13 (see Figure 10) of the fluids supplied to the bottom of column 1a 55 ascends in the tray section 1b and comes into contact with the tubular beam heat exchanger tube 8 in the high pressure column 1. In this case, the liquid in an arbitrary phase of the low pressure column 2 is introduced through the tube 24 into the portion of the lower tubena 8a of the heat exchanger 8. Therefore, the liquid in the tubena portion 8a is heated by the heat of the steam 13, and a portion of the steam 13 in contact with the tubena portion 8a condenses and becomes in liquid 14, which dec go. The upper pipe portion 8b 60 of the heat exchanger 8 is also heated by the heat of the steam 13. Therefore, the liquid introduced into

Through the tubena 24 in the heat exchanger 8 it changes to fluids that have a mixture of Kqida 12 and gas phase 11 while moving from the lower tube portion 8a to the upper tube portion 8b. The fluids are then passed through the pipe 25 which is located outside the column to enter the phase directly below the liquid extraction unit 2d of the low pressure column 2 (see Figures 7 5 and 9). A pressure supply means such as a pump is not needed to circulate said fluids, since the configuration uses the thermal siphon system.

In other words, since the liquid extraction unit 2d of the low pressure column 2 is connected to the lower pipe portion 8a of the heat exchanger 8 of the high pressure column 1 through the pipeline 10 24 and given that the upper pipe portion 8b of the heat exchanger 8 of the high pressure column 1 is connected to the phase directly below the liquid extraction unit 2d of the removal column 2 through the pipeline 25, the liquid drops from the low pressure column 2 to the high pressure column 1 by gravity, and the fluids that have passed through the heat exchanger 8 of the high pressure column 1 are circulated and moved from the high pressure column 1 to the low pressure column 2 by the effect of thermal siphon 15.

The distillation apparatus of the aforementioned embodiment provides the following effect. The high temperature steam through the compressor 4 is introduced directly into the heat exchanger 8 in the low pressure column 2, and the fluids flowing from the heat exchanger 8 are introduced into the bottom of the high pressure column 20 as described above, where heat is provided to the lower part of the low pressure column 2, and the fluids to be introduced into the lower part of the high pressure column 2 can also be cooled. A first heat transfer system (side heat exchange section) using the pipes 4a and 30 and the heat exchanger 8 in the low pressure column 2 is configured as if a lateral boiler was installed in the phase (it may be the lower or lower stage) of the lower part of the low pressure column 2, and a side condenser was installed in the phase (lower phase) of the lower part of the high pressure column 1. Therefore, compared with a distillation apparatus that does not include the first heat transfer system, the amount of heat that is removed can be reduced in the condenser 7 of the high pressure column 1, and the amount of heat that is supplied can be reduced in the Caldenn 3 of the low pressure column 2.

30 As described above, heat can be removed from the steam in the high pressure column 1 by the heat exchanger 8 in the high pressure column 1, and the heat can be transferred from the high pressure column 1 to the column of low pressure 2 through the pipeline 25. A second heat transfer system (side heat exchange section) using the tubes 24 and 25 and the heat exchanger 8 in the high pressure column 1 is configured as if it were installed a lateral condenser in the phase above the lower part of the high pressure column 35, and, simultaneously, as if a lateral caldenn was installed in a phase above the lower part of the low pressure column 2. By therefore, in comparison with a distillation apparatus that does not include the second heat transfer system, the amount of heat that is removed can be further reduced in the condenser 7 of the high pressure column 1, and the amount The heat that is supplied can be further reduced in the boiler 3 of the low pressure column 2.

40

Above all, the first heat transfer system described above that allows heat exchange between the lower part of the low pressure column and the lower part of the high pressure column, is configured to introduce the high pressure steam of the compressor 4 directly in the heat exchanger 8 of the liquid sump unit 2e provided in the low pressure column 2, and is configured to feed the condensed fluid 45 in the heat exchanger 8 to the high pressure column 1 (Figure 7 ). The configuration does not require a liquid head as in the example of the apparatus of Figure 2 as described in the SUMMARY OF THE INVENTION section, and, therefore, a corresponding improvement in energy saving performance can be expected. Compared to the configuration of the apparatus of Figure 5 which adopts the second heat transfer systems described above for all the heat exchange side sections 50 provided in the distillation apparatus, the energy saving performance is further improved.

According to the embodiment, the portion corresponding to the rectification section 2g can be operated under the pressure of the low pressure column 2 which is lower than the pressure of the high pressure column 1 as described above. Therefore, in comparison with the configuration of the apparatus of Figure 5, the relative volatility in the portion corresponding to the rectification section 2g becomes large, and the energy itself (amount of heat) that is originally needed for a process of separation can be reduced.

Figure 7 shows only two of the heat transfer systems described above. However, several equivalent heat transfer systems can be installed, for example, from 10 to 30% of the total number 60 of theoretical phases. It goes without saying that the amount of heat transfer systems to be installed and the

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locations of the heat exchanger and tubenas can be determined arbitrarily according to the design specifications.

The aforementioned apparatus of Figure 7 adopts the procedure that directly introduces the high temperature steam through the compressor 4 into the heat exchanger 8 at the bottom of the removal section of the low pressure column 2, and introduces the fluids leaving heat exchanger 8 to the bottom of high pressure column 1, so that the heat transfer system performs heat exchange between the side heat exchange section which is located in the lowest position in the removal section in the apparatus of Figure 5 and the side heat exchange section that is in the lowest position in the rectification section. However, the procedure can be adopted for a heat transfer system that performs heat exchange between the side heat exchange section that is located in the lowest position in the removal section in the apparatus of Figure 6, and the side heat exchange section that is in the lowest position in the rectification section, and the result is the configuration of the apparatus of Figure 8. The configuration does not require pressure loss as in the example of the apparatus of Figure 3 and, therefore, the energy saving performance can be improved as in the case of the apparatus of Figure 7. The portion corresponding to the rectification section 2g can be operated under the pressure of the low pressure column 2 which is lower than the pressure of the high pressure column 1 and, therefore, the energy itself (amount of heat) that becomes necessary for a separation process can be reduced as in the case of the apparatus d e Figure 7.

The heat integrated distillation apparatus described above is configured using the tray column or the packed column similar to that of the general distillation apparatus. This allows lateral cutting or multiple feeding without the need to improve the device, and allows easy maintenance of the device. For the same reason, the freedom to establish the number of phases for the high pressure column and the low pressure column allows optimization of the feeding phases. In other words, the present invention can solve problems 1) to 5) of the heat-integrated distillation apparatus using the double-pipe structure represented by JP2004-16928A.

According to the embodiments described above (Figures 7 and 8), the tube-type heat exchanger 8 is used as the component of the heat transfer system that transfers heat from the high pressure column 1 to the low pressure column 2. This allows free change of the heat transfer area A based on the design of the heat exchanger tubena 8. Therefore, to determine the amount of heat to be exchanged between the high pressure column 1 and the low pressure column 2, not only can the temperature difference AT be freely adjusted between the high pressure column 1 and the low pressure column 2, but also the heat transfer area A. Therefore, the present invention can solve the problem 6) of the heat integrated distillation apparatus using the double pipe structure.

According to the embodiments described above (Figures 7 and 8), the high pressure column 1 and the low pressure column 2, including the corresponding portion of the rectification column 2g, are connected to each other in the vertical direction. However, the present invention is not limited to this provision. In other words, the present invention includes an arrangement in which the high pressure column 1 and the low pressure column 2, including the portion corresponding to the rectification column 2g, are configured separately and independently.

Claims (5)

1. A heat integrated distillation apparatus comprising: 5 - a high pressure column (1) comprising a bottom of the column (1a), an upper part of the column (1c) and a packed or packed bed section (1b), said tray or packaged bed section (1b) used as a rectifying section; - a low pressure column (2), located above said high pressure column (1), said low pressure column comprising a bottom of the column (2a), a feeding phase (2f), a bed section in 10 tray or packaging (2b) used as a removal section and a portion corresponding to the rectification section (2g) located above the feeding phase (2f); - a first pipe (26) that connects the bottom of the column (1a) of said high pressure column (1) with the portion corresponding to the rectification section (2g) of said low pressure column through means (6 ) to supply a liquid that remains at the bottom of the column (1a) of said high pressure column (1) to the 15 portion corresponding to the rectification section (2g) of said low pressure column (2); - a heat exchanger (8) located in a phase at the bottom of said low pressure column (2); characterized in that the distillation apparatus further comprises: 20 - a second pipe (23, 4a) that connects the portion corresponding to the rectification section (2g) with said heat exchanger (8) in the lower part of the low pressure column (2); - a compressor (4) installed in said second pipe (23, 4a) and configured to compress steam from the portion corresponding to the rectification section (2g) and then supply the compressed steam to said heat exchanger (8) at the bottom of the low pressure column (2); Y 25 - a third pipe (30) that introduces fluid flowing from said heat exchanger (8) in the lower part of said low pressure column (2) to the bottom of the column (1a) of the high pressure column (1 ). 2. The heat integrated distillation apparatus according to claim 1, further comprising: 30 a second heat exchanger (8) which is located in a phase that is located above the bottom of the column (1a) of said high pressure column (1) to which said third pipe (30) is connected; a liquid extraction section (2d) that is located in a phase that is above the lower part of said low pressure column (2) to which said second pipe (23, 4a) is connected, and which extracts a part of the liquid from the phase outside the low pressure column; A fourth tubena (24) that introduces the liquid from said liquid extraction section (2d) to said second heat exchanger; Y a fifth tubena (25) that introduces fluid that passes through said fourth tubena (24) to be introduced into said second heat exchanger and then flows from the second heat exchanger to a phase directly below said extraction section of liquid (2d) of said low pressure column (2). 40 3. The heat-integrated distillation apparatus according to claim 1, further comprising a raw material supply pipe (27) that supplies a raw material at least to one of the top of the column of the removal section directly below the portion corresponding to the rectification section (2g) and a predetermined phase of one of the tray section and the bed section 45 packaging of the removal section. 4. The heat integrated distillation apparatus according to claim 1, further comprising a boiler (3) which is installed outside the bottom of the column of said low pressure column (2) and heats liquid at the bottom of the column. fifty 5. The heat integrated distillation apparatus according to claim 1, further comprising a condenser (7) that is placed outside the upper part of the column of said high pressure column (1) and cools the steam in the upper part of the column.